An oral glucose tolerance test in pregnancy and its association with future cardiovascular diseases

Aims/hypothesis: Gestational diabetes and abnormal 100-g oral glucose tolerance test (OGTT) results in pregnancy are associated with type 2 diabetes, but their relationship with cardiovascular disease (CVD) is less clear. We evaluated the risk of CVD according to the number of abnormal OGTT values during pregnancy. Methods: This retrospective cohort study used data from a major Israeli healthcare provider. Pregnant individuals aged 20–50 years without a prior diagnosis of type 2 diabetes and CVD who had a complete 100-g OGTT during their last pregnancy between January 2000 and December 2022 were included. The primary outcome was the development of a composite of CVD by September 2024. Risk was assessed using Cox proportional hazards models based on the number of abnormal OGTT values. Results: The study included 103 389 individuals with a mean age of 34 ± 5.2 years. Overall, the median follow-up was 6.8 years (IQR, 3.4–12.9), totalling 886 955 person-years. A composite of CVD developed in 641 individuals (a cumulative incidence of 0.62%). When compared to individuals with all OGTT values normal, individuals with one to three abnormal values had an adjusted hazard ratio (HR) of 1.2 (95% CI: 1.02–1.4) for CVD, reaching 2.41 (95% CI 1.44–4.05) in those with four abnormal OGTT values. Conclusions: A history of abnormal 100-gram OGTT results during pregnancy, and specifically having four abnormal values, is associated with an elevated risk of CVD. These results underscore the need for early post-partum identification and prevention strategies in this high-risk population.